Figure 3.

Experiment 3, Chemogenetic Inhibition of the AI Attenuates Targeted Helping. (A) Experimental 3 timeline. Male Sprague Dawley Observer rats underwent stereotax surgeries and received micro infusions of either the control virus (AAV8-CaMKIIα-EGFP, “EGFP”, n = 8) or the inhibitory DREADD virus (AAV8-CaMKIIα-hM4D(Gi), “hM4Di”, n = 10). After 3 weeks of recovery and viral incubation, rats went through the targeted helping task for 8 days. On the final 2 days of targeted helping, Observers received either clozapine-N-oxide (CNO) or water injections (i.p.) in a within-subjects experimental paradigm. Next, rats underwent a social reward place conditioning task (shown in Fig. 4). On the day animals were sacrificed, Observers were injected with either CNO or water and again performed the targeted helping task. (B) During the targeted helping task, Observers learned to release a distressed conspecific faster on days 3–8 compared to day 1. (C) On test days, Observers infused with the Gi DREADD injected with CNO had latencies significantly higher than their baseline (BL, days 7–8) and vehicle. There were no differences in eGFP viral control animals in response to CNO or vehicle. (D) Representative images of the AI in the viral control (EGFP) and hM4Di groups with either vehicle or CNO infusions. (E) 90 min following targeted helping, the animals were sacrificed to stain for c-fos in the AI to confirm both placement and activity of the inhibitory DREADDs by quantifying Fos + /Virus + cells as a percentage of total Virus + cells. Rats having received the Gi DREADD infusion and CNO injections 30 min prior to behavior had significantly fewer Fos + /Virus + cells compared to all other animals, indicating the DREADD construct was activated exclusively following CNO injection. *Significant difference from day 1, p < 0.05. #Significant difference from Veh and/or BL, p < 0.05